Valve rotator



E. ORENT Nov. 3, 1970 VALVE ROTATOR Filed Jan. 24, 1969 INVILN'I UR. 'dward 0mm. ,MW

I ATTORNEY "United States Patent Office 3,537,325 Patented Nov. 3, 1970 3,537,325 VALVE ROTATOR Edward Orent, Grand Rapids, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Jan. 24, 1969, Ser. No. 793,844 Int. Cl. F01! I/32; F16k 29/00 U.S. CI. 74-88 4 Claims ABSTRACT OF THE DISCLOSURE A coil spring returned and rocker actuated poppet valve having its stem slidably and rotatably guided in an engine cylinder head, including a valve rotator interposed between the return spring and a valve carried cap and comprising a Belleville spring fulcruming on a length of garter spring which seats against a helical ramp surface on the cap.

BACKGROUND OF THE INVENTION Field of the invention Description of the prior art Prior valve rotator devices are known which employ a Belleville spring and garter spring fulcruming :means therefor which act somewhat similarly under increased thrust load to free the valve and induce its rotation. U.S. Pat. No. 2,758,583 to Norton is representative of such rotators employing a circularly continuous garter spring seated in an annular groove normal to the valve.

SUMMARY OF THE INVENTION In accordance with my invention I have discovered that the rotation-imparting action of such prior rotators is significantly enhanced by providing the garter spring seating surface with a helical ramp and terminating shoulder or step. The advantage of the helical ramp ap pears to lie in its inducing a progressive, as contrasted to a simultaneous, tilting of the individual coils of the garter spring as the thrust load increases during valve opening movement, and the step at the end of the ramp contributes to the desired result in reducing slippage or slidable movement of the garter spring.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows, in section, a valve rotator embodying the invention and located between the coil spring and its retaining cap on a poppet valve guided for axial reciprocation and rotation in an engine cylinder head.

FIG. 2 is a sectional view of the rotator and upper portions of the return spring and valve, taken substantially along the line 22 of FIG. 1.

FIG. 3 is a sectional view taken substantially along the line 33 of FIG. 1 showing the stepped ramp surface for the garter spring in the valve cap.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in detail to the drawing, and first to FIG. 1, the numeral 1 designates a conventional poppet valve mounted for reciprocation and rotation in a guide 2 of an engine cylinder head 3. The valve is reciprocated by means shown in the form of a conventional coil return spring 4 acting in response to valve opening movements induced by an engine driven valve rocker 5. As shown, the return spring seats at its lower end against the cylinder head, and a member in the form of a retainer cap 6 is suitably fixed as by conventional wedging keepers 6 to the valve stem 7 above the upper end of the return spring.

The valve rotator of my invention comprises the cap member 6 which is modified for the purpose by having an annular groove 8 formed in its underside, the bottom of this groove being shaped to provide a helical ramp surface 9. Lying within the groove 8 is a length of garter spring 10 whose individual coils 11 are such diameter as to project out of groove when seated therein against the bottom or ramp surface 9. Groove 8 is located in a flanged portion 12 of the cap member which provides an annular shoulder 13 inwardly adjacent the groove. Underlying this shoulder and the garter spring 19 is a Belleville spring 14, which is shown as having a normally dished configuration, although this is merely a. design convenience to facilitate accommodating its flexure to a more flattened condition under increased loading in operation, Under minimum load (as shown, with the valve in closed position) this Belleville spring has engagement adjacent its radially inner extremity 15 with the cap shoulder 13, and at all loads it has engagement adjacent its radially outer extremity 1 6 with a washerlike element 17 seated on the upper end of the return spring 4.

The magnitude of the slope or helical angle of the 7 of only approximately zero degrees and 21 minutes for the purpose. In any event, the opposing ends of the ramp terminate in a connecting step or shoulder 18 facing one end 19 of the garter spring. This step or shoulder thus serves as a reaction point or abutment for the garter spring end 19, and it is preferable for such purpose that the garter spring be installed with its end 19 in abutment therewith. Preferably, for symmetrical loading reasons, both the groove 8 and garter spring extend substantially a full 360 degrees (as shown) about the valve, which also assures such abutment.

In operation, as the stem 7 is moved downwardly by the rocker 5 to effect opening of the valve '1 the increased thrust loading of the return spring 4 is transmitted by the washer-like element 17 to the Belleville spring 14. Initially, the Belleville spring transmits this increased thrust primarily to the cap member 6 by reason of its engagement with cap shoulder 13 adjacent the radially inner extremity 15 of the Belleville spring and the engagement adjacent the radially outer extremity of the Belleville spring with the element 17. The garter spring 10 has some of its individual coils 11 adjacen its opposite end 20 preferably under some initial compression at this point, at least enough to insure those ned coils being firmly seated against the portion of the ramp surface 9 adjacent the step 18 therein. Then with continued opening movement of the valve and resultant increased loading of the return spring and Belleville spring, further compression occurs in the individual coils adjacent the Belleville spring end 20, and this develops progressively to the next adjacent coils in sequential manner throughout the full length of the garter spring as the load continues to increase. Simultaneously, the coils of the garter spring, in resisting this load transmitted to the-m, serve as a fulcrum about which the Belleville spring deflects toward a more flattened configuration, with the result that the Belleville spring begins to move out of engagement adjacent its inner extremity 15 with the cap shoulder 13. Also, as the result of the increasing compressive load on them, the garter spring coils undergo a tilting action between the Belleville spring and the ramp surface 9, and thus a unidirectional rotation (counterclockwise as viewed in FIG. 3) is imparted to the cap member 6, keepers 6' and valve stem 7. By reason of the ramp surface having the aforementioned slope or helical angle such tilting action is made more positive and also caused to occur progressively from the end 20 to the end 19 of the garter spring. Also, by reason of the garter spring end '19 having abutment with the ramp step 18, the positiveness of this coil tilting and valve rotating action is enhanced because the garter spring is prevented from slipping circumferentially within the cap groove 8. After completing their tilting action, the garter spring coils accommodate re-engagement of the Belleville spring with the cap shoulder 13. Such engagement continues during reduction of the thrust load during reclosing of the valve, preventing retrograde rotation thereof.

What is claimed is:

1. 'In combination with a rotatably and reciprocably mounted member and reciprocating means therefor, a ramp surface fixed against rotation relative to one of said member and means, and helically disposed to the axis of their relative rotation, at length of garter spring extending concentrically of said axis and having its coils engageable with said ramp surface, and a Belleville spring concentric with said axis and spaced from the ramp surface by the coil spring, said Belleville spring being 30 in continuous thrust transmitting engagement adjacent one of its radially inward and radially outward extremities with said reciprocating means, the other of its said extremities normally being in thrust transmitting engagement with said member but movable out of engagement with said member in response to increasing thrust transmitted to the Belleville spring by the coil spring in response to axial movement of the member in one direction.

2. The invention of claim 1, wherein the Belleville spring is in said continuous thrust transmitting engagement with said means adjacent the radially outer extremities of the Belleville spring.

3. The invention of claim 2 wherein the opposite ends of the ramp surface terminate in a connecting step facing one end of the garter spring.

4. The invention of claim 3 wherein the ramp surface and garter spring extend substantially 360 degrees about said axis.

References Cited UNITED STATES PATENTS 2,397,502 4/1946 Ralston 123-188 2,758,583 8/1956 Norton 123-90 2,819,706 1/ 1958 Gammon 123-90 2,855,913 10/1958 Geer 123-90 2,881,745 4/1959 Allen 123-90 2,907,312 10/ 1959 Norton 123-90 3,421,734 l/1969 Updike et al. 251-337 AL LAWRENCE SMITH, Primary Examiner US. Cl. X.R. 

